Combustion chamber with multiple conical sections providing multiple air paths for gas turbines



July 1 COMBUST PROVIDING MULTIPLE AIR PATHS FOR GAS TURBI Filed Dec. 12, 1946 I I /9 z,

li i iil S. B. WILLIAMS ION CHAMBER WITH MULTIPLE CONICAL SECTION 2,603,064 was s Sheets-Sheet 1 ATTORNEYS.

Filed Dec. 12, 1946 3 Sheets-Sheet 2 July 15, 1952 s. B. WILLIAMS 2,603,064

COMBUSTION CHAMBER WITH MULTIPLE CONICAL SECTIONS PROVIDING MULTIPLE AIR PATHS FOR GAS TURBINES /0 i I 1 I 4 v x x 2 INVENTOR \SIGFIZUCI .3. h z'llz'ama.

BY MMJM ATTORNEYS.

u y 15, 1952 s. B. WILLIAMS 2,603,064

COMBUSTION CHAMBER WITH MULTIPLE CQNICAL SECTIONS PROVIDING MULTIPLE AIR PATHS FOR GAS TURBINES Filed Dec. 12, 1946 3 Sheets-Sheet 3 Goal INVENTOR- Samuel hillz ams.

Patented July 15, 1952 CO1VIBUS'1ION CHAMBER WITH MULTIPLE CONICAL SECTIONS PROVIDING MUL- TIPLE AIR PATHS FOR GAS TURBINES Samuel B. Williams, Detroit, Mich, assignor to Chrysler Corporation, Highland Park, Mich, a corporation of Delaware Application December 12, 1946, Serial'No. 715,873

(01. Gil-39.65)

' 22 Claims. 1

This application relates to a construction. designed to produce by a maximum degree of turbulence a satisfactory intermixing of different fluids. These fluids may be fuel and a combustion-supporting medium such as air, and the purpose .of the intermixing may be to facilitate as complete as possible a combustion of the fuel.

An object of the present invention is to provide improvements in .a construction that will create turbulent fiow of fluids for better mixing them.

Another object is to improve a burner by designing it to accommodate increased turbulence of fuel and a combustion-supporting medium.

A further object is to provide improvements in a burner tube and more specifically in openings in the wall of the burner tube through which air is admitted for greatest turbulent flow of the air and fuel.

Still another object is the provision ofa tube construction for admitting a combustion-supporting medium through the tube wall to fuel within the tube, which is cheap and easy to manufacture and affords the necessary opportunity for coolingand expansion .due to'heating.

Other obi ects will appear from the disclosure.

In the drawings:

Fig. 1 is a longitudinal sectional view taken on the line I-I of Fig. 2 showing the burner construction of the present invention;

Fig. 2 is a transverse .sectional view taken on the line 2-2 of Fig. 11,;

.Fig. 3 is an enlarged view showing a portion of Fig. 1;

.Fig. 4 is a sectional view partially in broken elevation of a first modification of the present invention; I

.Fig. 5 is an end view of a tubular section used with the first modification of the present invention;

Fig. 6 is a longitudinal sectional view showing a second modification of the present invention;

Fig. 7 is a transverse sectional view of the second modificationof the invention; and

Fig. 8 is a longitudinal sectional view showing a special use of any of the three forms of the present invention.

In Fig. .1 there is shown an outer tube 10 in which is mounted a fitting H carrying .a fuel nozzle 12. Also mounted :in the outer tube In is an :igniter I3. An inner tube is positioned-on the outer tube andincludes ata central region a plurality of short frusto-conical sections I5. The frusto-conical sections are nested one within .the other .and arezheldin spaced relation to :onean other by a plurality of spacing elements I6. As

seen in Figs. 2 and .3 there are six spacing elements I6 positioned about each frusto-conical section I5, and each spacing element comprises an attaching flange I1 by which the spacing element is suitably bonded to the exterior of the frustoconical section I5, an upstanding flange I8 which engages an adjacent frusto-conical section for maintaining the two .sections in spaced relation, and an extension or leg I9 by which the .frustoconical section is mounted within the outer tube ID in spaced relation thereto. Each leg or extension I9 is provided at its outer end with a flange 20 having a bent or curved end 2I for facilitating insertion of each frusto-conical section with its spacing elements I6 affixed thereto within the outer tube ID. The spacing elements I6 positioned about the exterior of a certain ,frustoconical section I5 are secured thereto, but they merely engage an adjacent frusto-conical section I5 without being joined thereto. Thus'adjacent frusto-conical sections I5 are not joined to one another, and so provision is madefor expansion and contraction as the temperature within the frusto-conical sections varies with the burning of fuel therein. The frusto-conical section at the left end of the inner tube It is designated'by the reference character 22 and will be seen to have a considerable length and to be curved at its small end and provided with a flanged opening 23 engaging. the fuel nozzle I2. The side of the ,frus'to-conical section 22 is also provided with a flanged opening, through which the igniter I3 projects. Near the right end of the inner tube 14 there is provided a .frustoconical section 25 having vanjintermediate section 26 of less slope than the end portion nesting within the adjacent .frusto-conicalsection I5, and a cylindrical-end portion (21. This portion .is engaged in overlapping relation by .an expanded end 28 .on a tube 29 which curves upwardly as indicated in Fig. l. The section.2.5 is spaced from the outer tube It by a bracket i252 As has been previously stated, the frusto-coni- I cal sections I5 are held in spaced relation from one another by means of the spacing elements I6, and thus there .is provided between each'pair of adjacent sections a frusto-conical annular space divided only by the upstanding flanges I8 on .the spacing elements 1.6. It is .to be noted that in Fig.1 the rightiendb-f eachfruste-conical section I5 is larger and surrounds the smaller left end of the next successive section.

The operationof the construction -j-ust described is as follows: an-appropriate fuel is .supplied through the fitting II and delivered from the fuel nozzle I2 into the inner tube I4. The igniter I3 starts the combustion of the fuel delivered by the nozzle I2, the combustion being supported by appropriate medium-such as air passing through the frusto-conical annular spaces between the sections I5 into the tube I4. This air comes from the outer tube III to which it may be delivered at its left end as viewed in Fig. 1, by appropriate means, not shown, at whatever pressure is found desirable. The air within the tube I moves from left to right, and so does the fuel in the inner tube I4 issuing from the nozzle I2. However, for the air in the outer tube I0 to pass between the frusto-conical sections I5 to the interior of the inner tube I4, it must travel from right to left, thus moving against the fuel within the inner tube I I. As a result of this opposition, vortices are set up at the inner ends of each of the annular spaces between the frusto-conical sections I5. These vortices are probably random rather than stable and thus good mixing of the air and fuel is effected. There is a large number of annular spaces between frusto-conical sections I5, which spaces are quite close to one another. Thus the energy of the random vortices is replenished before it is dissipated, for the proximity of the annular spaces one to the other causes the stream issuing from one annular space to intersect with or intersect the stream issuing from an adjacent annular space with the function of the annular spaces changing their respective identities as productive of mixing streams, combustion streams, and finally cooling dilutent streams as the progression of streams relatively nears end section 25 in the elongated inner tube.

It will be appreciated that the temperature of the inner tube I4 may be quite high when fuel is being burned within it. The use of short frustoconical sections I5, which are not joined to one another but engage one another only through the spacing elements I6 makes it possible for expansion and contraction to take place locally without setting up high stresses due to thermo distortion. The sections I5 are cooled by the air within the outer tube I0 passing over the outer faces of the sections and by the scrubbing or blanketing effect of the air as it enters the inner tube I4 through the frusto-conical spaces provided between the frusto-conical sections.

The burner construction of Fig. 1 may be used to good advantage in the power plant shown and claimed in the copending application of Staley and Williams, Serial No. 715,840 filed December 12, 1946, and thus the tubular member 29 of the inner tube I4 has been shown as curved. However, it is not necessary that the construction of Fig. 1 be used to drive the gas turbine of the said Staley and. Williams application, for it may be used to drive other turbines. Also its use is not limited to turbines, for it may also be used for certain other purposes. In fact, the construction may be used in any device that requires the mixing of any combination of fiuids.

In the modification of Figs. 4 and 5 the inner tube is formed at its intermediate region of a plurality of frusto-conical sections I5 which are spaced from one another by a plurality of short spiral flanged fins 30 which are bonded to the exterior of the various sections I5 but are not joined to the interior of the sections they contact. The spiral fins bonded to one frusto-conical section I5 extend in one direction and the spiral fins bonded to the adjacent frusto-conical section extend in the opposite direction. Positioning ele-' ments 3I separate from the spiral fins 30 are bonded to the exteriors of the frusto-conical sections I5 and extend outwardly and terminate in end portions 32 inclined somewhat to the outer tube It! for facilitating insertion of the frustoconical sections and maintenance thereof in the tube I0. As noted from Figs. 4 and 5 each frustoconical section I5 has secured to ita relatively large number of spiral fins 30. In the modification of Figs. 4 and 5 the frusto-conical sections face in the same direction as those of Fig. 1, and thus the flow of air from the outer tube III through the spaces between the frusto-conical sections I5 is opposed to the direction of flow of the fuel within the inner tube. In addition the spiral fins cause a swirling of the air as it enters the inner tube, and the direction of this swirl is reversed from one conical section I5 to the next. Thus a very high degree of mixing of the fuel and air is effected through the random vortices produced by the entrance of air in this manner.

In the specification of Figs. 6 and '1 the inner tube is formed at its intermediate region of sections 33, which have only a small degree of slope throughout the greater portion of their length and at their smaller ends a rather pronounced slope effected through a curved formation of the small ends, as indicated at 34. This arrangement produces an advantageous mixing of the fuel and air, and as in the case of the previous forms of the invention, the air will move in opposition to the flow of fuel as it passes between the sections 33. To each section 33 is attached a plurality of spacing elements 35 which have outwardly extending legs terminating in sloping portions 36 facilitating insertion and maintenance of the sections 33 within the outer tube I0. Each set of spacing elements 35 is joined only to the exterior of the section 33 with which it is associated; it is not joined to the interior of the adjacent section 33, that it engages. Thus there is provided the necessary freedom for expansion and contraction.

Fig. 8 illustrates how any of the foregoing forms of the present invention may be employed for producing coal gas. In this figure the outer tube In is divided in its length by a partition 31 which engages a frusto-conical section of the inner tube I4. A conduit 38 for air is connected to the outer tube In to the left of the partition 31 and a conduit 39 for steam is connected to the outer tube III as a reduced portion 40 conforming generally to the diameter of the frustoconical section of the inner tube I4 and being adapted to deliver coalgas. The fitting II and nozzle I2 deliver appropriate fuel such as powdered coal to the inner tube I4. The igniter I3 causes a combustion of the coal in the air coming from the conduit 38 and passing through the frusto-conical section adjacent the left end of the partition 31 of the inner tube I4. As the fuel and air pass in the inner tube I4 to the-right of the partition 31 they come in contact with steam passing through the frusto-conical sections to the right of the partition 31 and coal gas is the resultant product.

I claim:

1. In a burner assembly, the combination with a coextensive outer tube'and-an igniter and a nozzle positioned in the outer tube adjacent one end of the outer tube so -'as to be adapted to direct'fuel toward the other end thereof, of an elongated inner tube positioned in the outer tube in spaced relationthereto and containing the igniter and the nozzle and being formed of a succession of longitudinally aligned relatively short tubular sections of frusto conical shape overlapping one another with the small end of each successive section being nearer the nozzle and positioned within the large end of the next preceding section, and spacing means comprising means for maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of frusto-conical shape having the small end nearer the nozzle, whereby there is produced a plurality of annular paths for. a combustion-supporting medium extending from the space between the tubes to the inside of the inner tube in a direction opposite to the flow of fuel from the said one end of the outer tube toward the said other end thereof said paths being in axial sequence therealong by groups whereof the first two groups handle primary medium for mixing and combustion, respectively, as well as for cooling, and the third group introduces secondary medium thereafter purely for cooling purposes.

2. In a burner assembly, the combination with a coextensive outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct fuel toward the other end thereof, of an elongated inner tube positioned in the outer tube in spaced relation thereto and containing the nozzle and being formed of a plurality of longitudinally aligned relatively short tubular sections of frusto conical shape overlapping one another with the small endof each section nearer the nozzle, and spacing means comprising means for maintaining the overlapping portion of adjacent sections in radially spaced relation with the small end of each section being positioned within the large end of the next preceding section nearer the nozzle for forming between each adjacent pair of sections an annular space of frusto-conical shape having the small end nearer the nozzle, whereby there is produced a plurality of annular paths for a combustion-supporting medium extending from the space between the tubes inwardly to the inside of the inner tube in an upstream direc tion opposite to the flow of fuel from the said one end of the outer tube toward the other end thereof, said paths being in axial sections therealong by groups whereof the first two groups handle primary medium for mixing and combustion respectively as well as for cooling, and the third group introduces secondary medium thereafter purely for cooling purposes, the spacing means for the sections of the inner tube also comprising radiating legs with bent extensions projecting resiliently outwardly into frictional engagement with the outer tube fOr'maintaining the inner tube in properly spaced relation to the outer tube.

3-. An elongated right circular inner tube for a burner comprising a plurality of axially aligned tubular sheet metal sections of frusto-conical shape fitted one with another so as to be in overlapping relation and spacing means aflixed only to the outside faces of the sections comprising means for maintaining the overlapping portions of adjacent sections in longitudinally and radially spaced -relationfor forming between eachadjacent pair of sections an annular space for the entrance tothe tube of combustion-supporting l. A tube as' 'specified in claim 3 the spacing mean comprising 1 also means having radiating legs with bentextensions projecting-dutwardly of the tube so as to be adapted to act disengageably as a resilient friction held positio'ner for the tube.

5. In a burner assembly, the combination with an elongated outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct fuel toward the other end thereof, of an elongated inner tube positioned in the outer tube in spaced relation thereto and containing the nozzle and being formed of a plurality of relatively short axially aligned tubular sections of sheet metal of frustoconical shape overlapping one another with the small end of each section nearer the nozzle, spacing elements maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of frusto-conlcal shape having the small end nearer the nozzle, whereby there is produced a plurality of annular paths for a primarily combustion-supporting and subsequently secondarily pro'duct diluting medium extending from the space between the tubes to the inside of the inner tube in a direction opposite to the flow 'of fuel from the said one end of the outer tube toward the said other end thereof, and means anchored to the inner tube in the spaces between adjacent tubular sections and projecting outwardly therefrom into resilient frictional engagement with the. outer tube for maintaining the inner tube in longitudinally adjustable and radially spaced relation to the outer tube.

6. In a burner assembly, the combination with a right cylindrical outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct fuel toward the other end thereof, of an elongated inner tube positioned in the outer tube in spaced relation thereto and containing the nozzle and being formed of an axially aligned plurality of relatively short tubular sections of fru'sto-conical shape overlapping one another with the small end of each section nearer the nozzle, spacing elements maintaining the overlapping portion's of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of frusto-conical shape hav-'- ing the small end nearer the nozzle, whereby there is produced a plurality of annular paths fora combustion-supporting and products-cooling medium extending from the space between the tubes to the inside of the inner tube in a direction opposite; to the flow of fuel from the said one end of the outer tube toward the said other end thereof, and positioning elements separate from the spacing elements and being anchored to the inner tube in the spaces between adjacent tubular sections and projecting outwardly therefrom into resilient engagement with the outer tube for maintaining the inner tube in properly spaced relation to the outer tube.

7. A tube for a burner comprising a longitu dinally aligned plurality of tubular sections of frusto-conical shape fitted one with another so as to be in overlapping relation, spacing elements maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space for depending upon its "axial location the entrance to the tube of combustion-supporting or products diluting 'ga's, and positioning elements separate from the -'spacing elements and beinganchored to the inner tube -in the spaces between-adjacent tubular sections thereof and projecting outwardly therefrom so as to be adapted to act resiliently as an adjustable frictional positioner for the tube.

8. Ina; burner assembly, the combination with an outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct fuel toward the other end thereof, of an inner tube positioned in the outer tube in spaced relation thereto and containing the nozzle and being formed of a plurality of relatively short tubular sections of frusto-conical shape overlapping one another with the small end of eachsection nearer the nozzle, and guide vanes maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of a common size and frustoconical shape having the small end nearer the nozzle subdivided by thev guide vanes, one set of guide vanesspiralling in one direction and the next set of guide vanes spiralling in the opposite direction, whereby there is produced a plurality of annular paths for a combustion-supporting medium extending each the same distance of flow travel and attended by the same pressure drop from the space between the tubes to the inside of the inner tube in a direction opposite to the flow of fuel from the said one endof the outer tube toward the said other end thereof, and the one set of guide vanes causes the combustionsupporting medium to move spirally in one direction and the next set of guide vanes causes the combustion-supporting medium to move spirally in the opposite direction.

9. In a burner assembly, the combination with an outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct fuel toward the other end thereof, of an inner tube positioned in the outer tube in spaced relation thereto and containing the nozzle and being formed of a plurality of relatively short tubular sections of frusto-conical shape overlapping one another with the small end of each section nearer the nozzle, guide vanes maintaining the overlapping portions of adjacent sections in longitudinally and radially spaced relation for forming between each adjacent pair of sections an annular space of common size and frusto-conical shape having the small end nearer the nozzle subdivided by the guide vanes, one set of guide vanes spiralling in one direction and the next set of guide vanes spiralling in the opposite direction, and means anchored to the inner tube in the spaces between adjacent tubular sections and projecting outwardly therefrom into engagement with the outer tube for maintaining the inner tube in properly spaced relation to the outer tube, whereby there is produced a plurality of annular paths for a combustion-supporting medium extending each the same distance as to flow travel and attended by the same pressure drop from the space between the tubes to the inside of the inner tube in a direction opposite to the flow of fuel from the said one end of the outer tube toward the said other end thereof, and the one set of guide vanes causes the combustion-supporting medium to move spirally in one direction and the next set of guide vanes causes the combustion-supporting medium to move spirally in the opposite direction.

10. In a burner assembly, the combination with an outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adaptedto direct fuel toward the other end thereof, of a right cylindrical inner tube positioned in the outer tube in'spaced relation thereto and containing the nozzle and being formed of a plurality of relatively short tubular sections of frusto-conical shape overlapping one another with the small end of each section nearer the nozzle, guide vanes maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of common size and frusto-conical shape having the small end nearer the nozzle subdivided by the guide vanes, one set of guide vanes spiralling in one direction and the next set of guide vanes spiralling in the opposite direction, and positioning elements separate from the spacing elements and being anchored to the inner tube in the spaces between adjacent tubular sections and projecting outwardly therefrom into spring frictional engagement with the outer tube for maintaining the inner tube in resilient longitudinally positionable and radially spaced relation to the outer tube, whereby there is produced a plurality of annular paths for a combustion-supporting medium extending each the same distance as to flow travel so as to subject the individual divisions of the medium flow to the same low pressure drop as from the space between the tubes to the inside of the inner tube in a direction opposite to the flow of fuel from the said one end of the outer tube toward the said other end thereof, and the one set of guide vanes causes the combustion-supporting medium to move spirally in one direction and the next set of guide vanes causes the combustion-supporting medium to move spirally in the opposite direction.

11. A tube for a burner comprising a coaxial plurality of identical tubular sections of frustoconical shape fitted one within another so as to be in overlapping relation and guide vanes maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of common frusto-conical shape and size having the small end nearer the nozzle subdivided by the guide vanes, one set of guide vanes spiralling in one direction and the next set of guide vanes spiralling in the opposite direction. whereby the individual channels defined as from the outside of the tube to the inside are of the same length and similarly proportional shape.

12. A right cylindrical tube for a burner comprising a protracted plurality of equal tubular sections of frusto-conical shape fitted one'within another so as to be in overlapping relation, guide vanes maintaining the overlapping portions of adjacent sections in radially spaced relation for forming between each adjacent pair of sections an annular space of frusto-conical shape having the small end nearer the nozzle subdivided by the guide vanes, one set of guide vanes spiralling in one direction and the next set of guide vanes spiralling in the opposite direction, and positioning elements separate from the spacing elements and being anchored to the inner tube in the spaces between adjacent tubular sections and projecting outwardly therefrom into frictional engagement with the outer tube for maintaining the inner tube in longitudinally positionable and radially resilient spaced relation to the outer ube.

13. In a burner assembly, the combination with an outer tube and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adaptedtodirect fuel toward the other end thereof, of an elongated inner'tube positioned frusto-conical shape overlappingone anotherwith the small end of'ea'ch section nearer the nozzle, and spiral'g-ui de'vanes maintaining the overlapping portions of adjacent'sections in radially spaced relation ioriorming between each adjacent pair of sections a common sized annular space of frusto-conical shape having the small end nearer the nozzle subdivided by the guide vanes, whereby there is -produced a plurality of annular'paths of; equal extent for a combustionsupporting medium'extending from the space between the tubes to the inside of the inner tube in a direction opposite to the flow of fuel-from the said one end of the outer tube toward the saidother end thereof, and the spiral guide vanes causes the combustion-supporting medium to move spirally as it enters byway of the annular spaces.

l i. A burner assembly comprising in combination, an elongated outer tube, an elongated inner tube positioned in the outer tube in spaced relation theretmsaid inner tube having an upstream end and being provided with opening forming means in said end andmeans including a nozzle closing said opening means and said end, said nozzle being adapted to direct a, first fluid in the inner tube in a'fdirectien downstream of said inner tube endjth'e in'ner'tube furtherhaving spaced wall-forming members of frusto-conical shape arranged with the small end of each member positioned within the large end of the next preceding member toward the nozzle end of the inner tube, the adjacent members defining a series of circumferential paths therebetween for flow of a, second fluid from outer tube inwardly into the inner tube in a direction opposed to'the direction of the first fluid for admixing therewith, said series of paths being of suflicient downstream extent tor at least a part of said members to handle second fluid for diluting and cooling the resulting admixture of first and second fluids as ppropri e 15, A 'deviee for mixing'fiuidS Comprising an elongated right circular tube and means for directing a cone spray pattern of a first fluid in a stream through the tube from one end to the other, the tube having a succession of aligned frustoeconical sections arranged such that the small endof each successive section is positioned within thejlarge end of the next preceding section nearer the spray directing means, said succession of sections defining a series of annular openings in alignment, each opening extending from the said other end of the tube toward the said one end thereof when considered from outside to inside of the tube for supplying a second fluid through the tube wall in an upstream direction opposed to that of the first fluid in the tube to promote good mixing of the fluids, whereby at least a minor portion of the resulting admixture penetrates upstream of the path of said spray pattern for forming an effective admixture layer sweeping contiguous to the inner wall at said one end removed from the general mixing region.

16'. A burner assembly comprising in combination, an elongated outer tube, an elongated inner tube positioned in the outer tube in spaced relation thereto, said inner tube having an upstream end and being provided with opening forming means in the end aforesaid and means including an igniter and a nozzle closing said opening means and said end to a first fluid in said outer tube, said nozzlebeing adapted to direct a second fluid in the inner tube in adirection downstream of said inner tube end, the inner tube having wall-forming members of general frusto-conical shape in spaced relation to one another and arranged such that the small end oi each member is positioned within the large end of the next preceding member with respect tothe nozzle end of the inner tube, the adjacent wall-forming members defining a series of circumferential paths therebetween for flow of the first fluid from outer tube inwardly into the inner tube in an upstream direction relative to the direction of the second fluid. I 7

17. A. mixing device comprising an elongated inner tube, means for' directing a first fluid through the elongated innertube from one end in a cone pattern toward the other end, an elongated outer tube surrounding'and spaced from the elongated inner tube, the inner tube including a plurality of successively aligned sections or frusto-conical shape overlapping one another, and means maintaining the overlapping portions of adjacent sections in axially and radially spaced relation for forming between the sections, annular spaces of trusts-conical shape having the small end nearer the said one end of the inner tube, said sections being arranged with the small end of each successive sectionfpositioned within the large end of the next preceding section nearer the first fluid directing means'in order to direct a second fluid from the space between said elongated tubes at such a pressure in relation to the pressure of the fluid in the inner tube as to cause the second fluid to flow through the annular spaces into the inner tube in an upstream direction relative to the direction of the first fluid in the inner tube'and forming vortices in the latter thereby to be thoroughly mixed with the first fluid, at least a minor portion of the resulting admixture penetrating upstream of the path of said pattern for forming" an effective admixture layer sweeping contiguous to'theinnerface of the wall at said one end of the tube removed from the region of general mixing.

18. A mixing device comprising an elongated tube and means for directinga first fluid through the tube from one end to the other end, the tube including a plurality of axially aligned sections of f'rusto-conical shape overlapping one another with the small end of each section nearer the said one end of'the tube, and unitary spacing elements having leg portions radiating from'upstanding flange portions maintaining the over lapping portions of adjacent sections in longitudinally and radially spaced relation for forming between the sections congruent annular spaces of frusto-conical shape having the smaller end nearer the said one end of the tube, whereby a second fluid may flow through the annular spaces into the tube in a direction opposed to the direction of the first fluid and thereby be thoroughly mixed with the first fluid, the leg portion of each of said spacing elements having a bent free end presenting a portion adapted for frictional engagement whereby efiorts resulting from a centripetal press may be resiliently opposed, the upstanding flange portion of each of said spacing elements engaging the interiors and exteriors of the frusto-conical sections and being bonded only to the exteriors of the frusto-conical sections for providing for necessary relative shifting of the sections due to temperature'changes. Y

19. A combustion device comprising an elongated outer tube and an igniter and a nozzle positioned in the outer tube adjacent one end of the outer tube so as to be adapted to direct a first fluid toward the other end thereof in a cone pattern terminating in a, region of admixture of established proportions predetermined according to a fixed ratio, and an elongated inner tube positioned in the outer tube in spaced relation thereto and containing the igniter and the nozzle, the inner tube having a series of successively aligned irusto-conical sections forming the walls of the inner tube and being arranged with the small end of each successive section positioned within the large end of the next preceding section nearer the nozzle and defining between successive sections of the series a plurality of annular openings of frusto-conical shape having the smaller end nearer the nozzle, whereby there is produced a plurality of annular paths through the walls or the inner tube for a second fluid from the outer tube to the inner tube, which annular paths are opposed in direction to the flow of the first fluid from the nozzle, at least a. portion of said plurality discharging at a point, as regards the direction of flow of said first fluid, downstream of said region, said region constituting an area of combustion for said first fluid with said portion handling air for diluting the resulting products of combustion.

20. In a mixing and burner assembly, the combination with a right cylindrical combustion tube having a wall with means defining an extended series of coaxial toroidal passages of equal size in longitudinal alignment, said wall terminating in a coaxial bell-shaped closed casing having a central and an offset aperture, of a nozzle adapted to direct fuel through said central aperture in a cone pattern occupying the central region of said casing'and the wall, an igniter recessed in said ofiset aperture without the direct path of said cone pattern, and of means maintaining an ambient atmosphere for said tube under pressure whereby at least a portion of the resulting fiow is directed by said wall means to scrub said casing and igniter.

21. In a. burner assembly, the combination with a right cylindrical combustion tube having a wall with means defining an extended series of coaxial toroidal passages of equal size in longitudinal alignment, said wall terminating in a coaxial bell-shaped closed casing having a central aperture of a coaxial outer housing surrounding said tube in radially spaced relation, and a nozzle positioned in the housing and embraced by said aperture so as to be adapted to direct fuel along 12 said extended series, said housing being adapted to be maintained under pressure whereby combustion supporting and pure cooling medium is furnished to within the tube, said wall means directing the great bulk 01' medium in counterfiow relation for the combustion zone, yet reserving a portion for counterflow introduction into the resulting products of combustion and at a pressure drop of the identical order as encountered by said great bulk,

22. An elongated combustor comprising a tube assembly having an inner flame chamber and an air chamber in surrounding relationship thereto, a discharge dome at one end of the flame chamber having a continuous side wall, an end wall, and an opening opposite said end wall 01 an area at least as great as the said cross-sectional area of said discharge dome at all points between said end wall and said opening opposite, a fuel conduit having spray aperture means centrally of said discharge dome extending in a direction to direct a spray of fuel towards said opening, and a stack of cone sections nesting together in spaced relationship and fitted with one end of the stack within said opening in the discharge dome, the small end of each section being positioned within the large end of the next preceding section nearer the discharge dome of the flame chamber and overlapping in a manner such as to form passages between successivesections which are inclined to direct air from the air chamber inwardly and in an upstream direction into the flame chamber with respect to the fuel spray.

SAMUEL B. WILLIAMS.

REFERENCES CITED The following references are of record in the file of this patent:'

UNITED STATES PATENTS Number Name Date 1,289,037 Mosher Dec. 24, 1918 2,111,432 Macchi Mar. 15, 1938- 2,268,464 Seippel Dec. 30, 1941 2,404,335 Whittle July 16, 1946 2,475,911 Nathan July 12, 1949 2,477,584 DeZubay Aug. 2, 1949 2,531,810 Fyfie Nov. 28, 1950 FOREIGN PATENTS Number Country Date 376,570 Germany May 30, 1923 691,430 Germany May 25, 1940 

